The concept of an automated highway system (AHS) has been fervently pursued. Although the interpretation of the AHS concept varies from one person to another, people implementing the concept are incorporating more and more technology into an automobile to improve its operations, better its safety measures, and add conveniences to the vehicle user.
A prevalent interpretation of the AHS concept is hands-free driving. To that end, magnets have been buried along an experimental automated highway, and automobiles have been equipped with magnetometers to sense the magnets to guide the moving vehicles, thereby obviating manual steering. In another approach, an automobile is equipped with a video system in which cameras monitor different segments of the road ahead and feed images to on-board computers that control steering, acceleration and braking of the vehicle.
Although the above hands-free driving systems are at various stages of development and will be made available to the public in years to come, a less comprehensive system known as an “adaptive cruise control system” will soon be publicly available. This system is capable of adjusting a vehicle's speed to keep it moving with the flow of traffic. Specifically, it relies on radar or infrared sensors to measure the distance to the vehicle just ahead. If the vehicle ahead speeds up or slows down, an onboard computer adjusts the throttle or brakes to maintain a safe distance,
Although the ultimate AHS is in the works, it is believed that the building blocks therefor are in place. These building blocks include the well-known “drive-by-wire” system, TRAXXAR stability control system, global positioning satellite (GPS) navigation system, etc. The drive-by-wire system refers. to a throttle system responsive to electrical control signals to adjust the speed of a vehicle, and plays a major role in the aforementioned adaptive cruise control system.
In the TRAXXAR system, sensors are used to measure the steering wheel position, yaw rate and lateral acceleration of the vehicle. These sensors work with an onboard computer to controllably apply brakes at selected wheels to avoid potential skids.
In a well-known manner, the GPS navigation system receives signals from a constellation of satellites. In response to such signals, the navigation system pinpoints the vehicle's location (in latitude and longitude). It also detects the vehicle's speed and direction. With geographic information stored on an onboard computer, the navigation system is capable of verbally and visually communicating to the user instructions for reaching the destination.